Mechanical stoker.



v H. ISERMAN.

MECHANICAL STOKER.

APPLICATION FILED SBPT 11, 1911.

1,1 14,142, l Patented Oct. 20, 1914i` mener HARVEY ISERMN, 0F NEW HYDEPARK, NEW YC'Et-K, ASSIGNR '.lO MULTIPLE-GRATE-l BAR ENDLESS CHAIN STOERCOMPANY, A. CORPORATION OF NEW YORK.,

MECHANICAL STOKER.

trinite'.

y to improvements in the construction and mounting of the retardingplate or bridge, located Yat th'e rear of the traveling grate. Theobjectof my invention is to provide a retarding plate or vbridge which.shall be of fire resisting material and the parts of which shall be.economical to construct and easy and convenient to replace.

Further objects of my invention will hereinafter appear in thespecificationiand be pointed out in the appended claims.

Figure 1 is a vertical section through the rear part of a furnace and astoker embodying my invention, taken on a. plane between the travelinggrateand the side frame; Fig. 2 is a. front view of the retarding plateor bridge, 'partially broken away to show the manner of attaching thelire brick to the supporting plate; and F ig. 3 is an enlargedperspective of the fire bricks employed in the construction of theretarding plate, or bridge.

As shown in the drawings, llis a steam boiler mounted in the usualfurnace structure,"of which l have shown only the side walls 2 and thebridge wall 3 vwith its bridge 4' over which the products of combustionescape to the stack. The endless traveling grate, which may be of anyAdesired type is indicated at "5. The grateI runs over rear sprockets 6mounted on a sprocket shaft 7 journaled in the grate frame. The grateframe is composed of upper horizontal members 8 and lower horizontalmembers 9, joined by standards 10. I havel shown the frame as made ofiat plate but' any desired form of structural iron or steel may beemployed. The upper horizontal member 8 is continued beyond the rearstandard 10 a `sufficient distance to form a' support,

through the angle 13, for the-rear plate 11 which forms the front 'wallof the ash pit and also carries the supports for the retard- Snecicationof Letters Patent.

Application led Septemberll, 1911.

raten-tea 0015.20, 1914, Serial N0. 643,747.

ing plate or bridge. Plates 12 riveted to ,the`

standards ldopposite the lower'members;

9 also serve to support the plate 11 through the angle 13 to which 11Iis riveted. Riveted to the rear side of plate 11 are angles 14, (one oneither side vof the furnace) and the shelf 15. The side plates 16 of theash chamber are secured to the angles 14 and to angles 17'attached tothe bridge wall 3. The

ash chamber thus has front wall 11, rear wall 3 and side walls 16. Theash chamber has a flo-or 18, whichl swings against-the A shelf 15 and ishinged at 19 to supports 2() on the Wall 3 in suchmanner as to permitdumping of ashes into the ash car 23 whr i1 desired, but to normallyclose the opening in the bottom of the ash chamber and preivent thestack. p

On endless traveling grates the fuel `bed decreases in thickness fromfront to rear due to consumpton of the coal; and it is of importancethat it should not become too passage of air there through to the thinat the rearfor the reason that an eX- cess of air would then pass upthrough it, resulting in a'loss of eliciency. In order to thicken thefuel bed by backing up the ash and partially consumed fuel, and also toreduce as much as possible the opening for the passageof air behind thegrate to the flue, I provide a retarding plate or bridge 24. I Thisbridge comprises a metallic bottom plate 25, carrying special lire brick26 (of which four are shown though any desired number may be employed).The plate 25 is provided with a plurality of straps 27 into which fittrunnion pins 28 projecting from standards 29 bolted to'the plate 11.The retarding plate or bridge is thus mountedto swing about thetrunnion.Q 28 in order that any obstruction, as for instance, an'unusual accumulation of clinker, may be .allowed to pass thereunder, soas not to damage the nose N of the brick 26. As

"shown, the pivot point much to the rearof that the nose N oit' theretarding plate approaches very closely to, but just misses contact withthe traveling grate or bridge; the relative distance between these twoelements being slightly exaggerated in Fig. 1 for the sake of clearnessot' the drawing.

The fire brick 26 which form the heat resisting face of the retardingplate or bridge are clearly shown in perspective in Fig. 3. The recesses32 (one on either side of each brick) receive bolts 33 vfor attachingthe brick to the bottom plate 25. Slots 34, passing the entire width ofthe brick, receive, a rib 35 on the bottom plate to which rib istransmitted the horizontal thrust exerted against the brick. I ha'veshown the rib 35 as being formed by an angle iron bolted to thebot-tomplate 25, but it may be formed of other suitably shaped iron, or may beintegral with the bottom plate if desired.

yAsbestos packing 36 is placed around bolts 33 and angle 35 and betweenthe bricks 26 and` the plate to provide a slightly resilient mediumtherebetween and to lessen the conductionjof heat tothe plate 25. The

- brick are also grooved or iuted at 37 to provide air passages underthe` brick to aid in the cooling of plate 25.

ajo

The manner of operation of the device is apparent. 'Ihe ashes andpartially consumed fuel are carried forward by the grate, the directionof travel of which is indicated by Athe arrowl A. As the grate andretarding plate are in such close proximity, the ashes, to escape fromthe grate, must pass over the front inclined surface of the retardingplate.

which they are from time to time dumpedl by dropping the plate 18.

I am aware that it is old, in connection with mechanical stokers of theendless trav* cling grate type, to provide retarding plates or bridgesof metal or water cooled metal. But, inucase that uncooled metal isemployed it is soon burned out; and, when hollow water cooled structuresare employed, there is liability of scale forming and the vparts burningout. When such accidents occur leaks result which are diliicult andexpensive to repair and which necessitate allowing the fire to go out.In my construction there are no water cooled parts to get out of orderand the metal parts are not exposed to the high heat of the combustionchamber.

Having thus described mv invention, what I claim is l. In a mechanicalStoker, an endless travcling grate, a frame for supporting said grate, arear plate carried by said frame, stops and trunnions mounted on saidrear plate, a bottom plate mounted on said trunnions and normallyengaging said stops, and

a covering of lire resistant material for said bottom plate.

2. In a mechanical Stoker, an endless travcling grate, a frame forsupporting said grate, a rear plate carried by said frame, stops andtrunnions mounted on said rear plate, a bottom plate mounted on saidtrun nions and normally engaging said stops,

springs mounted on said rear plate and tending to return the bottomplate to engagement with the stops, lire brick mounted ou the bottomplate, means for securing the fir'e brick to the bottom plate and meansfor preventing displacement o'f the re brick on tl` bottom plate.

In testimony whereof, I hereunto aiiix my signature in the presence oftwo witnesses.

HARVEY ISEE-MAN. Witnesses:

NORMAN BRowN, A. L. ROGERS.

